Also consider with refresh rate if you're going to be starting at it for hours and hours lower refresh rates can cause headaches. I have to have a refresh rate of 75 and above to not get a headache.
As
Isokolon said higher pixel density is higher picture quality.
It also matters how much RAM and what Mhz it is.
My PC has 16GB 3600MHz DDR4 which will render 4k Ultra but a slight lag/delay depending on the amount of detail and size of image.
(works outstandingly good for the old school games I like to play that have very clean VGA and EVGA graphics.)
With 32 GB RAM 4400MHz DDR4 it is a very noticeably difference in render time.
check out the link below for more detailed information about pixel density...